Malignant pleural mesothelioma (MPM) is an aggressive and rare form of cancer which arises from environmental fibrous minerals (tremolite asbestos or erionite) exposures. Since it is difficult to differentiate the benign pleural thickenings from carcinomas, MPM can only be diagnosed in the advanced stage. Therefore, it is important to develop a new method with high specificity and sensitivity for the early diagnosis of MPM. Fourier Transform Infrared (FTIR) spectroscopy is a novel and non-invasive method that provides high specificity and sensitivity in the diagnosis of cancer. Moreover, FTIR with its attenuated total reflectance (ATR) tool is eminent technique because of its rapidity and ease to put into clinical practice. Hence, we used ATR-FTIR spectroscopy coupled with chemometric analysis methods to characterize the molecular alterations as well as to differentiate the experimental groups from each other. FTIR spectra of the samples collected from patients diagnosed with malignant pleural mesothelioma (MPM), lung cancer (MLC), benign, and healthy control (C) were recorded in the 4000-650 cm-1spectral region.. Recording the spectra and analysis of the spectral data were obtained with Perkin Elmer Spectrum One Program. Spectral analysis indicated a significant decrease in the lipid, protein, carbohydrates, and nucleic acid contents in MLC and MPM with respect to the healthy samples. Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) were performed to differentiate the studied groups based on the spectral differences. HCA of the samples demonstrated that all studied groups successfully differentiated from the control. Moreover, successful clustering of the all groups (control, MLC, MOC, MPM) was obtained in the protein region (1900-1485 cm-1 and 3500-3010 cm-1) by PCA of serum samples.